SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9e9881935379897bc9c844bffec11cbee11f48d200cb3ae2302616813ccea3a' 
  AND token = '4st0oa+JoGek1e18lFXldADtV9zrxROujZ8yGPqVXYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}